The present invention is directed toward improvements in the striking mechanism of the piano and related instruments wherein a mechanism is provided for a string or other sound producing member to be struck in response to depression of a key.
The striking mechanisms that are presently used in pianos may be characterized as a movement which enables the pianist to put expression into the music being played and which can provide many years of use without malfunction. Although the mechanisms are somewhat varied as to complexity, the piano's history extends to the early part of the eighteenth century from which it evolved until approximately the first quarter of the nineteeth century into a design which has remained basically unchanged to the present time.
It was the desire of the early piano makers to afford the pianist control over the duration of his notes. Thus, a hammer was needed which would strike the string and immediately fall away even while the key remained depressed. Upon release of the key, simultaneous application of a damper to the vibrating string must be had in order to terminate the particular note. To facilitate striking of the strings, a more difficult task than damping, two mechanisms evolved as the piano began to develop.
One of these, the jack mechanism, involved a lever, or jack, which was mounted beyond the pivot point of the key. Immediately above the head of the jack was the shank of the hammer. The shank was generally mounted by a hinge behind the point of contact of the jack, and the hammer itself was carried at the opposite end of the shank of the jack. Depression of the key raised its extremity and the jack which imparted impetus to the hammer, throwing it against the string. Simultaneous with its movement the jack also raised the damper from the string to permit vibration. The hammer, having struck the string, fell away to rest upon the raised jack. Subsequent release of the key, brought the jack away from the hammer and permitted the damper to repose against the string.
This system had its disadvantages, however. The hammer had to be positioned at some distance from the string so that it could not bounce off of the jack to strike the string a second time, and to prevent the jack from breaking the shank. This required the keys to be struck firmly and a short period of time for the hammer to return to its place making a soft touch and rapid repetition of a note impossible.
The second mechanism, known as the double escapement system, remedied both of the disadvantages inherent with the jack mechanism. The escapement system is characterized by a lever which throws the hammer against the string as did the jack, but unlike the latter, the lever slips away or escapes from the hammer after moving it and is thereafter free from control by the key.
Perhaps the only disadvantage of the double escapement mechanism is in the number of components necessary to produce each note which varies from about 50 to more than 80, depending upon manufacturers. It is understandable that large expenditures of labor are necessary to manufacture the components and assemble the striking mechanisms, greatly adding to the cost of the instrument. Despite rising costs of labor and the necessary materials, little if any attention has been devoted toward simplification of the mechanism.
One such design which greatly decreased the number of components for a striking mechanism has been described in my earlier U.S. Pat. No. 3,757,026. Although the former mechanism could readily be manufactured and substituted for existing units in a piano, it was believed that an escapement action was not necessary inasmuch as a fair rapidity of repetition was afforded the pianist for all notes without sacrifice of expression. It is now believed that a suitable escapement action would be desirable as well as several other improvements which should benefit the pianist as well as the manufacturer.